From the books of Joseph E. Muscolino, DC 4/13/2015 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY Roles of Muscles 1 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 1 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Define the key terms of this chapter and state the meanings of the word origins of this chapter. • Describe the relationship between the role that a muscle plays and the action in question. • Compare and contrast the roles of mover and antagonist. • Discuss the concept of cocontraction. 4/13/2015 Objectives 2 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 2 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • State the muscle that is working during the action in question. • Describe the relationship between gravity and joint actions. • Explain the application of tight antagonists to restricted joint motion. • Compare and contrast the roles of fixator and neutralizer. 4/13/2015 Objectives 3 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 3 Mover Muscles • Movers: muscles that can do the action in question • Can shorten in two ways: • Concentrically contract and shorten • Relax and shorten • For every joint action, a functional group of movers can contract to make the action happen. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 4 Mover Muscles (cont’d.) • Most powerful mover = prime mover • Other movers = assistant movers • Movers are also known as agonists. Figure 13-1 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 5 Figure 13-1 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Mover Muscles (cont’d.) 6 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 6 Antagonist Muscles • Antagonists do the opposite action of the action in question. • Can lengthen in two ways: • Eccentrically contract and lengthen • Relax and lengthen • Sometimes called contralateral muscle (opposite side) Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 7 Antagonist Muscles (cont’d.) • Most powerful antagonist = prime antagonist Figure 13-2 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 8 Figure 13-2 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Antagonist Muscles (cont’d.) 9 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 9 Antagonist Muscles (cont’d.) • Contraction: when the agonist and antagonist contract at the same time • Not considered healthy • The same as pressing gas and brake pedals simultaneously Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 10 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Muscle that is working = muscle that contracts during the action in question • Easiest way is to examine gravity’s role in the action in question 4/13/2015 Determining the “Muscle That Is Working” 11 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 11 4/13/2015 Determining the “Muscle That Is Working” (cont’d.) • Upward movements, movers work and antagonists relax • Horizontal movements, movers work and antagonists relax • Downward movements, antagonists work and movers relax TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Three general rules: 12 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 12 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Determining the “Muscle That Is Working” (cont’d.) Figure 13-3 13 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 13 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Determining the “Muscle That Is Working” (cont’d.) 14 Figure 13-3 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 14 4/13/2015 Stopping Unwanted Actions of the “Muscle That Is Working” • Fixators stop action at fixed attachment • Neutralizers stop action at mobile attachment • Example: flexion of the fingers into a fist TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Fixators and neutralizers both stop unwanted actions of working muscle 15 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 15 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Describe the general concept of the relationship between fixators and neutralizers and the muscle that is working. • Give an example of a fixator and a neutralizer relative to a specific joint action. • State the step-by-step method for determining fixators and neutralizers relative to a specific joint action. 4/13/2015 Objectives 16 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 16 Fixator Muscles TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 • Fixators: stop unwanted action at the fixed attachment of muscle that is working • Also known as stabilizers • Contract isometrically Figure 13-4 17 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 17 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Fixator Muscles (cont’d.) In the illustration on the right, the posterior deltoid acts as a fixator of the arm by creating a force of extension on the arm at the shoulder joint. This prevents Figure 13-4 Figure 13-5 the biceps brachii from flexing the arm at the shoulder joint. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 18 18 ● Which muscle is acting as the fixator in this figure? The rectus abdominis. TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Fixator Muscles (cont’d.) Figure 13-6 ● Why? 19 It prevents the TFL from anteriorly tilting the pelvis. ology of the musculoskeletal system: foundations for physical rehabilitation, ed 2, St Louis, 2010, Mosby Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 19 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Mobility (phasic) muscles: larger, longer, more superficial • Postural stabilization (tonic) muscles: smaller, deeper, closer to joints • Core stabilization, strength, and efficiency of movement • Core stabilization and spinal health 4/13/2015 Concept of Fixation and Core Stabilization 20 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 20 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Concept of Fixation and Core Stabilization (cont’d.) Modeled from Neumann DA: Kinesiology of the musculoskeletal system: foundations for physical rehabilitation, ed 2, St Louis, 2010, Mosby If we stabilize our core’s axial body, then we can channel all the strength of our muscles’ contractions toward moving our Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. extremities. All rights reserved. 21 21 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Concept of Fixation and Core Stabilization (cont’d.) 13-8 If the vertebrae in this scenario are Figure not fixed, then they will move every time the arm abducts. This can eventually result in excessive wear and tear and therefore toInc.,the spine. Copyright © 2011,damage 2007 by Mosby, an affiliate of Elsevier Inc. All rights reserved. 22 22 ● There are three cardinal planes: sagittal, frontal, and transverse. If we assume that the desired action occurs in one of these planes, we should also recognize that undesired actions might occur in the other two, were it not for the presence of neutralizers. TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Neutralizers stop unwanted action at the mobile attachment of the muscle that is working. • They create a contraction force equal in strength but opposite in direction to the force of the unwanted action. 4/13/2015 Neutralizer Muscles 23 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 23 In B (on the right), why is the sternocleidomastoid (SCM) a Figure 13-9 neutralizer? It is a neutralizer because it cancels out unwanted actions of the right levator scapulae. (Neck flexion cancels out neck extension, and left rotation of the neck cancels out right rotation of the neck.) Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Neutralizer Muscles (cont’d.) 24 24 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Neutralizer Muscles (cont’d.) Which muscle is the neutralizer in the illustration on the left? The pronator teres is the neutralizer because its action of pronation of 13-10 Figure 13-11 action of the forearm at theFigure radioulnar joints cancels out the biceps brachii’s supination of the forearmCopyright at the radioulnar joints. © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 25 25 Determine the action in question. Determine the muscle that is working and its role. Determine the fixed and mobile attachments. List all actions of the muscle that is working, and state whether the actions are desired or undesired. TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • • • • 4/13/2015 Step-by-Step Method for Determining Fixators and Neutralizers 26 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 26 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Determine the action of each fixator at the fixed attachment. • Choose a muscle that can do the action determined for each fixator. • Determine the action of each neutralizer at the mobile attachment. • Choose a muscle that can do the action determined for each neutralizer. 4/13/2015 Step-by-Step Method for Determining Fixators and Neutralizers (cont’d.) 27 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 27 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Step-by-Step Method for Determining Fixators and Neutralizers (cont’d.) 28 Figure 13-12 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 28 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Describe the role of a support muscle. • Explain the two ways in which a synergist can be defined. • Compare and contrast synergists and antagonists for a given joint action. • Explain the concept of coordination as it relates to the role of muscles. • Describe the possible clinical effects of isometric contractions. 4/13/2015 Objectives 29 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 29 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Define and give an example of a 2nd-order fixator. • Explain why it is difficult to isolate a specific muscle contraction; further, explain and give an example of how muscle contractions tend to spread through the body. • Discuss and give an example of the concept of coupled actions in the body. 4/13/2015 Objectives 30 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 30 Support Muscles • Hold another part of the body in position while the action in question is occurring • Do not work directly at the joint • Oppose the force of gravity on a body part • Contract isometrically ● Support muscles usually work far away from the joint where an action is occurring. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 31 The left-sided erector spinae musculature supports this action. TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 Support Muscles Figure 13-13 Figure 13-14 Its force of left lateral flexion of the trunk at the spinal joints prevents the trunk from falling into right lateral flexion of the trunk at the spinal joints. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 32 32 Synergists • Synergists: muscles or forces that work with the muscle that is contracting • Example #1: Biceps brachii and pronator teres Figure 13-15 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 33 Synergists • Example #2: Right external abdominal oblique and left internal abdominal oblique In the sagittal plane, these muscles are synergists. In the frontal plane, however, they are antagonists. Figure 13-15 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 34 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Muscles rarely act in isolation. • A number of muscles may contract for any given joint action. • Coordination is the co-ordering of muscles in the body in their various roles to create smooth and efficient movement. 4/13/2015 Coordinating Muscle Roles 35 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 35 TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY • Clinical effects of isometric contractions • Close off veins for the entire length of contraction • Buildup of toxic waste products • Waste products irritate nerves 4/13/2015 Coordinating Muscle Roles 36 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 36 Coordinating Muscle Roles • 2nd-order fixators Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY One way to explore the complexity of coordination is to lift a heavy weight in your right hand (as shown in the illustration) and slowly palpate the pronator teres, biceps brachii, posterior deltoid, and left erector spinae. You will be able to feel each of these muscles as they work in concert to lift the weight. 4/13/2015 • Fixators that fix attachments of fixator or neutralizer muscles Figure 13-16 37 37 Coordinating Muscle Roles TCCD MASSAGE THERAPY PROGRAM MSSG 2014 KINESIOLOGY 4/13/2015 In the soccer scenario, what is the role of the support muscle? It is keeping the player from falling to the ground. 38 Figure 13-17 Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 38 Coupled Actions • Two separate joint actions that must occur simultaneously ● Abduction of the arm 180 degrees relative to the trunk really consists of two separate coupled joint actions. ● What are they? The two separate coupled joint actions are abduction of the arm at the 13-18 scapula at the scapulocostal shoulder joint and upward rotationFigure of the joint. Copyright © 2011, 2007 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. 39